SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8af4eafab6ffcb06baf4e975974219b513173d5900eb9046f03291710fcf6df1' 
  AND token = 'JoVuiea75ptKHnHTh6FWjkE/S3sxiesjXMYhBO/b2aY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}